Method of severing rubber



May 11 1926.. 1,584,371

R. T. GRIFFITHS METHOD OF SEVERING RUBBER Filed Augustv 12, 1925 wwntoz @11 VldMmM/Mhw euromunt Patented May 1l, 1926.

UNITED STATES RICHARD T. GRIFFITHS, OF AKRON, OHIO, ASSIGNOR T0 THE MILLER 1,584,371 PATENT OFFICE.

RUBBER corr- PANY, OF AKRON, OHIO, A. CORPORATION OF OHIO.

METHOD OF SEVERING RUBBER.

Application filed August 12, 1925. Serial No. 49,781.

My present invention relates to improvements in methods of cutting rubber. Heretofore this has been a difficult operation due to the tendency of the rubber to stick or adhere to the surface of the cutting implement.

I have discovered that if a severing element is heated to and maintained at a certain temperature and pressed against the rubber, the latter will be broken down or melted when it contacts with the heated element, which will pass readily through the rubber, analogous to a cutting action, but much more eflicaciously, as the progressive melting or breaking down of the rubber results in the production of an oily substance which facilitates the passage of the severing element.

The invention includes the novel method hereinafter described, and particularly defined by the appended claims.

In order that the invention may be more readily understood, reference is made to accompanying drawings, in which Figure 1 is an elevation (partly in-section) showing 'what I at present consider the best form of severing instrument for carrying out my improved process.

Fig. 2 is a section on line 2 2 of Fig. 1.

Fig. 3 is a section on line 3-3 of Fig. 1.

Fig. 4 is diagrammatic of the device in operation.

Referring to this drawing, the numerall 1 designates a suitable handle of insulating material which supp Orts the severing element. in the shape of a relatively thin blade 2 of electric resistance metal designed to be heated by the passage of electric current which is supplied thereto by the conductors 3, 3 connected to a suitable source of current through a current controlling device or rheostat, whereby the temperature of the severing loop may be regulated.

The loop may conveniently be formed of nichrome wire, though it will be understood that I do not limit myself to this material. It will also be understood that by the term wire I do not mean to limit myself to any particular shape in cross section, though that shown is desirable.l

In practice I prefer to support the blade in the manner shown in the drawings, in which the handle encompasses a frame comprising parallel members 4 and `5 having odset ends 4f and 5a, to which the ends of the the member 6, the nut being provided with a spring enclosing skirt 7 a.

In carrying out the process the current is turned on till the resistance element is heated to the desired degree, preferably a cherry red, and one side of the knife is pressed against the edge or side of the rubber to be cut, whereupon it quickly penetrates and passes through the rubber. I have found that the action will be facilitated if the instrument is reeiprocated during such pressmg as this tends to keep the temperature of the lresistance element even, due to the ortions thereof which pass into and out o the` rubber.

A specific example of cutting is illustratedv in Fig. 2, wherein I have shown at R a plurality of rubber sheets confined between pattern plates 8 and 8a, an edge or the edges of which serve as a guide for the severing device. Such pattern plates I make of heat resisting material such for example as asbestos board, which will not be injured by the heat or reduce the temperature of the severing element, as the latter contacts with the edge of the pattern and follows the contour thereof.

Having thus described my invention, what I claim is 1. The hereindescribed method of cutting rubber which consists in pressing thereagainst at the point to be severed a relatively narrow severing element and maintaining said element at a temperature which will break down the rubber without burning the same.

2. The hereindescribed method of cutting rubber which consists in pressing thereagainst at the point to be severed, a severing element of wire like shape which is maintained at afcherry red heat during the severing operation.

3. The hereindescribedmethod of cutting or severing rubber, which consistsin applyrigidly secured to the oii'set frame4 ing to a surface of the rubber a pattern of heat resisting material, and pressing against the rubber and in contact with and'guided by said edge, a severing element heated to a temperature sufficient to melt the rubber.

4. The hereindescrbed method of cutting rubber sheets, which consists in confining the sheets between pattern plates ofv heat resisting material :1nd pressing a severing element against the rubber and in Contact with an edge of the pat-tern while maintaining said severing element at a temperature sufiicient to melt the rubber.

In testimony whereof, I affix my signature. v

RICHARD T. GRIFFITHS. 

